Jack



G. F. KUEHN.

JACK.

APPLICATION FILED IAN. 5. 1921.

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HHH

ATTORNEY UNITED STATES PATENT GFFICE.

GEORGE F. KUEHN. 0F SPRINGFIELD, MASSACHUSETTS, ASSIGNOR T0 LEON W. ROSENTHAL, 0F SPRINGFIELD, MASSACHUSETTS.

JACK.

T 0 a?? whom if 'may concern Be it known .that l.' GEoRGE F. KUEHN, a citizen of-the ll'nited States, residing at 22 Crestwood4 Street. Springfield. in the county of Hampden, State .of Massachusetts. have invented certain new and useful llmprovcments in Jacks; and I do hereby declare the following to be a full. clear, and exactdescription of the invention. such as will enable others skilled in the art to which it appel-rains. to make and use the same.

Thepresent invention relates to jacks. and particularly to jacks of the telescopic kind havinga housing with two or more spindles adapted for longitudinal movements relatively to each other Tand to the housing for the purpose of providing a large extension with a comparatively small collapsed height.

While jacks of this general kind are known, the means heretofore provided to prevent undue outward movement l of the outer spindle to an unsafe. or unstable position. in case the operator should attempt to lift the load beyond the intended range of the jack usually consisted of a nut threaded upon the inner end of the spindle. ln ac` cordance with this part of my invention. spring means are provided for limiting the outward movement of one spindle. said means preferably7 comprising a spring ring arranged at the lower end of the outer spindle so as to prevent an undue binding action between the outer spindle and the housing when starting to lower the jack from its fully extended position. 4 V lrrespective of the foregoing features. but preferably in combination therewith, the inr relation also comprehends a structure in to move relatively7 thereto,'with the result which a nut is detachably fastened on top of the housing, the outer spindle having an external thread throughout substantially its entire length. and also having an internal thread near the top only for engagement with an inner spindle which is externally threaded for substantially its entire length. lin this way the total length of screw threads is reduced to a minimum. and the housing may have its compression partof smoothbore cast iron and its screw-threaded part of a separate piece betteradapted for the punl pose.

Heretofore no' means have been provided to compel the total longitudinal movement of one spindle before another spindle starts Specification of Letters Patent. Patented June 2()a 1922 Application led January 5, 1921.

Serial No. 435,246.

that the comparatively great specific fric` tion at the threads of an inner spindle. due to its reduced diameter relatively to that of an outer spindle. sometimes causes'the two or more spindles to rise simultaneously or alternately, thus produc/ing an uneven and rtherefore a jerky movement by the operator. ln accordance `with this part of my invention, and irrespective of the other features enumerated herein. all but one of the spindles are prevented from rising at a time by resilient means or by a clutch. which is overcome or disengaged when the rising .spindle reaches a predetermined point of its relative longitudinal movement. whereupon another of the spindles is then released for longitudinal movement to further extend the jack.

ln the case of a jack having two spindles, as specifically' described hereinafter. the spring-pressed plunger or disengageablel clutch may be arranged between the housing and the outer spindle. and may be released when'the inner spindle reaches its outer limit of travel in the outer spindle and reengaged when the outer spindle reaches its collapsed position. Preferably such a spring-pressed plunger is carried by the housing and isarranged to enter a hole in the outer spindle when that spindle is collapsed. and to be disengaged from the outer spindle when that spindle is turned after the inner spindle reaches its outer limit of travel. For instance. as specifically described hereinafter. the nut fastened to t-he housing may contain the plunger and a collar or flange at the top of the outer spindle may have the hole to resiliently lock it until the inner spindle. at-,its upper limit of travel. exerts a disengaging turning force on the outer spindle. ln this way the beginning of the lift of the outer spindle is made subservient to or dependent upon the. position of the inner spindle.

In the accompanying drawings illustrating the preferred form of my invention in fapplication, as'an example. to a jack having two spindles and particularly adapted for trucks,

Fig. 1 is a sectional elevation of the jack collapsed; Figft). is a. similar view of the jack fully7 extended: Fi :3 is a view'on line 3 3 of Fig. l; and Figs. l and 5 are enlarged sections on lines l-l and respectively. of Fig. l. i A

The smooth-bore cast iron housing 1 car 4. snaps into the hole 8 to resiliently lock the` outer spindle against turning' in the nut.

The. spring ring embraces the lower end of the outer spindle 6 and has one of its ends bent over and projecting into the hole l1 (Fig. 5) to prevent the outer spindle from screwing beyond full engagement with the nut 4. when it is pressed against the lower surface of the nut in the fully raised position of the outerv spindle (Fig. 2).

The outer spindle 6 is externally screwthreaded throughout substantially its entire length for engagement with the nut 4. and has an internally screw-threaded upper portion 12.

The solid steel inner spindle '13. which is screw-threaded throughout most of its length for engagement with the internal threads of the outer spindle. has an enlarged lower portion 14 arranged to frictionally engage the lower surface of the portion 12 of the outer spindle: and a neck 15 carrying at its outer end a relatively rotatable load-engaging block 16 having a ball 1T spring-pressed into the peripheral groove 18.

Mounted fast on the neckl. just below the load-engaging block 16. isa ratchet pinion 19 which is engaged by one or the other arms of a reversible yoke pawl 20 pivoted on the stud 21. An operating handle comprises a frame 22 loosely journaled on theneck 15 and carrying besides the stud 21 a springpressed plunger 23 which holds the pawl 20 in a set position. The handle-also car-` ries a downwardly offset socket 24 for receiving a bar 25 with a spring-pressed ball 26 adapted to enter a groove 27 to resiliently retain the bar in the socket.

To extend the jack from the fully collapsed position shown in Fig. 1. the reversible pawl is set to turn the pinion 19 and the inner spindle 13 in the direction indicated by the arrows in Figs. 1 and 3. the bar 25 being oscillated bythe operator. The plunger 9 then resiliently holds the outer spindle 6 against turning. lVliether or not the block 16 engages the load. the inner spindle 13 continues to rise to its outermost position relatively to the inner spindle. at which time. the enlarged portion 14 frictionally engages the under surface of the enlarged upper portion 12 of the outer spindle. This gripping action is sufficient to disengage the collar 7 from the plunger 9. forcing the plunger out of the hole 8 as the collar begins to turn. The outer spindle 6 then rises in vposition as shown in Fig. 2.

the housing. lifting. the inner spindle 13 with it. until the spring ring 10 comes into contact with the under surface of the nut 4, the jack then being in its fully extended It is obvious from the foregoing that the load may be lifted from the fully collapsed position of the jack to the fully extended position thereof. or to any intermediate point of that extension.

To collapse the jack from its fully extended or any intermediate position. the pawl 20 is reversed so-as to turn the pinion 19 in the directionindicated by the arrow in Fig. 2. As a result of the binding action then existing between the lower portion 14 and the under surface of the enlarged portion 12. the outer spindle is screwed down in the housing until the plunger 9 snaps into the hole 8. The binding friction between the spindles is then overcome by a slight additional turning effort. whereupon the same direction of operation of the rod 25 lowers the inner spindle 13 in the outer spindle 6 until the jack is fully collapsed as shown in Fig. 1.

IVhat I claim is:

1. In ajack, a housing. an outer spindle longitudinally movableA in said housing. an inner Spindle in screw-threaded engagement with said outer spindle. means for limiting the outward movement of said inner spindle in said outer spindle, means for limitingthe outward movement of said outer spindle in said housing, one of said means embodying a spring, and means for rotatin said inner spmdle.

2. In a jack, a housing, an outer spindle longitudinally movable in said housing,l a spring-.ring fastened to the lower end of said outer spindle foi` limiting the out-- ward movement Vof said outer spindle in Asaid housing, an inner spindle in screwthreaded engagement with said outer spindle, means for limit-ing the outward movement of said mner spmdle 1n said outer spindle, and means for rotating said inner spindle.

3. In a jack. a smooth-bore housing, a nut detachably fastened on top of said housing. an outer spindle having an upper portion with an internal thread and also'having an .external thread throughout substanhousing, an inner spindle adapted for longi' tudinal movements in the outer spindle, a disengageable clutch constructed and arranged to hold one spindle against longimaar te tudinal movement untilthe other spindle has reached substantially its outer limit of longitudinal movement to become disengaged upon further movement ofv said other spindle. and means for rotating the inner spindle. n

5. In a jack, a housing. an outer spindle adapted for longitudinal movements in said housing, a load-engaging spindle adapted for longitudinal movements in the outer spindle. resilient means oonstructed and arranged to hold one spindle inst longitudinal movement until the other spindle has reached substantially its outer limit of longitudinal movement, and means for rotating the inner spindle.

6. lln a jack, a housing, an outer spindle adapted for longitudinal movements in said housing, an inner spindle adapted for longitudinal movements 1n the outer spindle, mid outer spindle and housing forming two members one of which has a hole and the other of which carries a spring-pressed plunger adapted to enga e said hole in one of the extreme longitu inal positions of the outer spindle. and means for rotating the inner spindle.

7. ln a jack. a'housing, an outer spindle adapted for longitudinal movements in said housing, an inner spindle adapted for longi tudinal movements in the outer spindle, a disengagealole clutch between the housing and the outer s indle to hold the outer spindle against t e longitudinal movement in the housing until the inner spindle has reached substantially its outer limit of longitudinal movement 1n the outer spindle, to become disengaged upon further move ment. of said inner spindle and means for rotating the inner spindle.

, 8. ln a jack, a housing, an outer spindle top of said housing. a sprung-pressed plunger located in said nut, an outer spindle adapted tor longitudinal movements in said housing and having an upper collar with a hole arranged to be engaged b v the plunger when u the outer spindle is colla sed. an inner spindle adapted for longitudlnal movements in the outer spindle, and means for rotating the inner spindle. i

10. lin a jack; a smooth-bore housing; a nut fastened on top of said housing; a spring-pressed plunger carried b v said nut; an outer spindle externall)v threaded throughout substantially its entire length for engagement with said nut and having an upper portion with a iange andan internal thread, said dange having a hole adapted to 'he engaged h said plunger in the collapsed position o the outer spindle, an innerspindle externally threaded throughout substantially its entire length for engagement With the internal threads of the upper portion of said outer spindle. said outer spindle having means limiting its upper movements in said housing and the inner spindle having means limiting its out/er movements in the outer-spindle; and

means for rotatin the inner spindle.-

lln testimony Wiereof I aix my s1gnature.

GEORGE F. KUEHN. 

